Bosman Arjan J, Snik Ad F M, Mylanus Emmanuel A M, Cremers Cor W R J
Department of Otorhinolaryngology, University Medical Centre Nijmegen, The Netherlands.
Int J Audiol. 2006 Aug;45(8):429-37. doi: 10.1080/14992020600673189.
The performance of the most powerful Bone-Anchored Hearing Aid (BAHA) currently available, the BAHA Cordelle, was evaluated in 25 patients with severe to profound mixed hearing loss. Patients showed bone conduction thresholds at 500, 1000 and 2000 Hz, ranged between 30 and 70 dB HL, and an additional air-bone gap of about at least 30 dB. With the BAHA Cordelle, free-field thresholds improve relative to bone-conduction thresholds with 1.5, 5.0, 17.8, and 4.3 dB at 500, 1000, 2000, and 4000 Hz, respectively, with substantial inter-individual variability. The differences in unaided air conduction thresholds and aided free-field thresholds amount to 45.3, 45.8, 47.5, and 43.5 dB at 500, 1000, 2000, and 4000 Hz, respectively. Speech perception, measured both with monosyllables of the consonant-vowel-consonant type and with bisyllables, showed highly similar results. The fitting range of a (linear) hearing aid is determined by its gain characteristics. Requiring aided speech reception thresholds at or better than 65 dB SPL results in an upper limit of the fitting range of the BAHA Cordelle for bone-conduction thresholds of 51, 56, 67, and 58 dB HL at 500, 1000, 2000, and 4000 Hz, respectively. The dynamic range provided by the BAHA Cordelle was estimated from loudness growth functions at 500, 1500, and 3000 Hz employing 7-point categorical scaling. On average, aided loudness growth functions exhibit normal slopes but they level off at input levels of about 80, 70, 65 dB SPL for 500, 1500, and 3000 Hz stimuli, respectively. Measurements with a skull simulator demonstrated that the levelling-off reflects saturation of the output of the Cordelle. The relatively low saturation levels of the device suggest that increasing maximum output levels may be a worthwhile consideration for candidates with more profound sensorineural loss.
对目前市面上功能最强大的骨锚式助听器（BAHA）Cordelle型在25例重度至极重度混合性听力损失患者中进行了评估。患者在500、1000和2000赫兹的骨导阈值在30至70分贝听力级之间，且气骨导差约至少为30分贝。使用BAHA Cordelle型助听器后，在500、1000、2000和4000赫兹时，自由声场阈值相对于骨导阈值分别提高了1.5、5.0、17.8和4.3分贝，个体间差异较大。在500、1000、2000和4000赫兹时，未佩戴助听器时的气导阈值与佩戴助听器后的自由声场阈值之差分别为45.3、45.8、47.5和43.5分贝。使用辅音-元音-辅音类型的单音节词和双音节词进行测量的言语感知结果高度相似。（线性）助听器的适配范围由其增益特性决定。要求助听听阈在65分贝声压级及以下，这导致BAHA Cordelle型助听器在500、1000、2000和4000赫兹时，骨导阈值适配范围的上限分别为51、56、67和58分贝听力级。通过采用7点分类标度，根据500、1500和3000赫兹的响度增长函数估算了BAHA Cordelle型助听器提供的动态范围。平均而言，助听听度增长函数呈现正常斜率，但在500、1500和3000赫兹刺激下，分别在约80、70、65分贝声压级的输入水平时趋于平稳。使用颅骨模拟器进行的测量表明，这种平稳反映了Cordelle型助听器输出的饱和。该设备相对较低的饱和水平表明，对于感音神经性听力损失更严重的患者，提高最大输出水平可能是一个值得考虑的因素。
